The website Northampton Underground Railways begins:
The Northampton Underground was a railway system which ran in tunnels under the streets of Northampton from 1904 until 1934.Sadly, that is not true. There never were any underground railways in Northampton even if this photograph, borrowed from the site, appears to show one being built.
But you have to admire the industry and imagination of whoever has produced the site. I found it while researching the old Northampton Corporation transport offices.
And whoever it is, he is no stranger than whoever it is who is pretending to revive the Snailbeach District Railways. He left many comments - using different names - here and here.